Queue management system and method

ABSTRACT

The invention provides a data visualisation system comprising a data value memory in which is maintained a finite set of data values obtained from monitoring apparatus and a display configured to display a representation of each data value centered on respective data points. The invention also provides a contour generator which in one form is configured to generate and display a contoured representation around each data point such that each data point is displayed as a local maximum and in another form is configured to generate and display one or more contour lines around each data point, each contour line representing data values which are less than the data value of the data point around which the contour line is displayed. The invention also provides related methods and computer programs.

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application is a continuation of International ApplicationNumber PCT/NZ01/00263, filed on Nov. 26, 2001, which claims priority toNew Zealand Application No. 508429, filed on Nov. 24, 2000, the contentsof both applications are incorporated herein by reference.

FIELD OF INVENTION

[0002] The invention relates to a data visualisation system and method,particularly but not solely designed for use in assessing and analysinghuman activity such as queues of people, crowds attending an event, foottraffic through a space, individuals loitering in an area, and so forth.

BACKGROUND TO INVENTION

[0003] The low cost of data storage hardware has led to the collectionof large volumes of data. Merchants, for example, generate and collectlarge volumes of data during the course of their business. To competeeffectively, it is necessary for a merchant to be able to identify anduse information hidden in the collected data. Where the merchantoperates retail premises, this data could include operational parameterssuch as the length of customer queues, the average waiting time in aqueue, the average service time and so forth. The data could alsoinclude information on the areas in which customers prefer to browsewithin a retail premises. The task of identifying this hiddeninformation has proved very difficult for merchants.

[0004] U.S. Pat. No. 5,097,328 to Boyette describes a system whichperforms image processing of camera images. The system is designed foruse in businesses which include queues or servers and has a camera whichcaptures successive images of an area to be monitored. A combination ofblob analysis and motion analysis is used to determine if a server is onduty and present at the server's station, and if the server is serving acustomer. Using blob analysis techniques, the system is able to maintaina count of the number of people waiting in the queue to be served. Thedata is used to generate displays directing waiting customers to thenext available server and to inform newly arriving customers of theirexpected waiting time.

[0005] U.S. Pat. No. 5,953,055 to Huang et al/NCR Corporation describesa system for detecting, collecting information about, and analysing aqueue. A sequence of video images from a video camera are converted intodigital video images and pixel processing and edge detection areperformed, regions separated by less than a defined pixel distance aregrouped into single objects, and the number of objects are counted todetermine the number of persons in an area, for example a queue. Thesystem can collect data on the number of people in the queue, theaverage service time for each person in the queue, and other types ofinformation regarding the queue.

[0006] U.S. Pat. No. 5,864,616 to Hartmeier/Intel Corporation describesa system which collects data on call activity, for example the number ofcalls waiting in a queue, the time duration of the oldest call still inthe queue, and a site identifier. The system displays these statisticsto a user in a display which uses features such as colour to indicatethe current state of calls waiting to be served and the longest callwaiting.

[0007] The systems described above are largely focused on the captureand storage of data representing human activity. None of these systemsprovide a means of display of the captured and stored data in a formwhich is intuitive and easy to interpret.

SUMMARY OF INVENTION

[0008] In one form the invention comprises a data visualisation systemcomprising a data value memory in which is maintained a finite set ofdata values obtained from monitoring apparatus; a display configured todisplay a representation of each data value centred on respective datapoints; and a contour generator configured to generate and display acontoured representation around each data point such that each datapoint is displayed as a local maximum.

[0009] In another form the invention comprises a data visualisationsystem comprising a data value memory in which is maintained a finiteset of data values obtained from monitoring apparatus; a displayconfigured to display a representation of each data value centred onrespective data points; and a contour generator configured to generateand display one or more contour lines around each data point, eachcontour line representing data values which are less than the data valueof the data point around which the contour line is displayed.

[0010] In a further form the invention comprises a data visualisationsystem comprising a data value memory in which is maintained aninteraction database of interaction data representing interactionsbetween customers and merchants, the interaction data obtained frommonitoring apparatus; a retrieval device configured to retrieve from theinteraction database data representing interactions between customersand merchants and to construct a finite set of data values from theretrieved data; and a display configured to display a graphicalrepresentation of at least one merchant and to superimpose one or morecontoured representations of the data values on the graphicalrepresentation of the merchant such that each data value is displayed asa local maximum.

[0011] In another form the invention comprises a method of datavisualisation comprising the steps of maintaining in a data value memorya finite set of data values obtained from monitoring apparatus;displaying a representation of each data value centred on respectivedata points; and generating and displaying a contoured representationaround each data point such that each data point is displayed as a localmaximum.

[0012] The invention in a further form comprises a method of datavisualisation comprising the steps of maintaining in a data value memorya finite set of data values obtained from monitoring apparatus;displaying a representation of each data value centred on respectivedata points; and generating and displaying one or more contour linesaround each data point, each contour line representing data values whichare less than the data value of the data point around which the contourline is displayed.

[0013] In a further form the invention comprises a method of datavisualisation comprising the steps of maintaining in a memory aninteraction database of interaction data representing interactionsbetween customers and merchants, the interaction data obtained frommonitoring apparatus; retrieving from the interaction database datarepresenting interactions between customers and merchants; constructinga finite set of data values from the retrieved data; displaying agraphical representation of at least one merchant; and superimposing acontoured representation of the data values on the graphicalrepresentation of the merchant such that each data value is displayed asa local maximum.

BRIEF DESCRIPTION OF THE FIGURES

[0014] Preferred forms of the data visualisation system and method willnow be described with reference to the accompanying Figures in which:

[0015]FIG. 1 shows a block diagram of a system in which one form of theinvention may be implemented;

[0016]FIG. 2 shows the preferred system architecture of hardware onwhich the present invention may be implemented;

[0017]FIG. 3 is a preferred representation generated in accordance withthe invention; and

[0018]FIG. 4 is a flowchart of a preferred form of the invention.

DETAILED DESCRIPTION OF PREFERRED FORMS

[0019]FIG. 1 illustrates a block diagram of the preferred system 10 inwhich one form of the present invention may be implemented. The systemincludes one or more clients 20, for example 20A, 20B and 20C, whicheach may comprise a personal computer or workstation described below.Each client 20 is connected to a network or networks 30 as shown. It isenvisaged that network(s) 30 could comprise a local area network or LAN,a wide area network or WAN, an Internet, Intranet, wireless accessnetwork, or any combination of the foregoing.

[0020] The preferred system 10 further comprises a data repository 40,for example a data warehouse maintained in a memory. It is envisagedthat the data repository may alternatively comprise a single database, acollection of databases, or a data mart. The preferred data repository40 includes data from a variety of sources. The data repository mayinclude, for example, data obtained from monitoring apparatus forexample visual input apparatus 42, audio input apparatus 44, trafficcounting apparatus 46, pressure sensitive apparatus 48 and/orinteraction data 50 representing interactions between customers andmerchants which in one form could comprise interactions betweencustomers and merchants over a telecommunications network for example apublic switched telephone network or PSTN or other communicationsnetwork.

[0021] One preferred form of the invention comprises a personal computeror workstation 60 operating under the control of appropriate operatingand application software having a data memory 62 interfaced to a server64, the workstation interfaced to the network(s) 30. The invention couldinclude a retrieval device or component 66 which in one form comprises asoftware-implemented query enabling retrieval of data from the datarepository 40. The data retrieved using the retrieval device 66 isprocessed with the server 64. A contour generator 68 which in one formcomprises a computer-implemented software program generates a contouredrepresentation or series of contour lines in order to display arepresentation of the data on a client workstation 20 as will bedescribed below.

[0022] The invention in one form comprises the workstation 60 which isarranged to retrieve data from the data repository 40, to process thedata with the server 64 and to display the data on a client 20 as willbe described below. It is envisaged that the raw or processed data couldbe stored in the data memory 62.

[0023] In another form the invention comprises a software product eitherinstalled or operating on workstation 60 or arranged to be installed andoperated on the workstation. The invention in another form comprises amethod of retrieving the data from the data repository 40, processingthe data and displaying the data on a client 20 using the workstation60.

[0024] As described above, the system 10 could include visual inputapparatus 42. Examples of such visual input apparatus include videocameras, electronic eyes, infrared cameras, motion detectors and lightbeam sensors. Generally a predefined monitored area will be selected forthe monitoring of human activity within that selected area. Suchactivity could include a queue of people standing in a line or clusterwaiting for some service or product. The human activity could alsoinclude a crowd attending an event, or could include one or moreindividuals loitering in a predefined monitored area. Video cameras andother visual input apparatus could be directed toward the monitored areain order to capture data representing human activity within that area.

[0025] For example, a merchant may operate a commercial premises andwish to monitor the behaviour of customers within the merchant premises.By positioning one or more video cameras at strategic locations withinthe merchant premises, the merchant can obtain information aboutcustomers in the commercial premises. The merchant could position avideo camera to capture images of customers waiting in line to beserved. By performing image processing on successive captured imageframes, various parameters of customer behaviour can be obtained. Forexample, the length of the queue, the average waiting time in the queue,the average service time and the queue falloff can all be estimatedsimply by image processing on successive frames captured by a videocamera directed at a customer queue. Such parameters are referred to askey performance indicators or KPIs.

[0026] By positioning several video cameras around a merchant premises,the merchant can also perform further processing on image frames fromthese further video cameras to obtain information on the number ofcustomers travelling through different areas or locations in themerchant premises and the length of time that each customer spends atthese different locations.

[0027] By using the same video cameras, the merchant can obtain data onthe unauthorised entry of individuals on the merchant premises outsideof usual trading hours. The point of entry can be readily ascertained,and those parts of the monitored area in which the unauthorised personor persons travel can also be readily ascertained.

[0028] In addition to or as an alternative to visual input apparatus 42,the system 10 could also include data captured by audio input apparatus44. Such audio input apparatus could include one or more microphones forrecording audio inputs within a monitored area. Such audio inputs havean advantage over visual input apparatus in that they are more readilyconcealed by a merchant. Inputs from microphones can be analysed andstored in the data repository 40 as audio files or equivalent to locatethe presence of one or more persons within the monitored area and canalso give an indication of the number of persons and the state ofagitation or general mood by the volume of noise.

[0029] The system 10 could also include inputs from traffic countingapparatus 46 such as turnstiles or ticketing machines and the datastored in the data repository 40 from the traffic counting apparatus 46could include the number of individuals through a monitored area withina given time frame.

[0030] The system 10 could also include inputs from pressure-sensitiveapparatus 48 for example floor-mounted sensor pads. Data captured fromthe pressure-sensitive apparatus 48 is stored in the data repository 40and gives an indication within a monitored area where individuals traveland how long individuals spend in the areas monitored by the sensorpads.

[0031] The system 10 could also include interaction data 50, for examplequeue statistics of callers put on hold in a telecommunications networkfor example a public switched telephone network or PSTN or othercommunications network, or a queue of applicants for an Internetservice.

[0032] The data repository 40 could comprise data values obtained fromany one or more of the above methods. In this way, some of the datavalues could be obtained from one method whereas other data values couldbe obtained from another method. In each case, the data values stored inthe data repository 40 could include time and/or date values. Theinvention is arranged to retrieve these data values from the datarepository 40 and to display either animated visual images or stillimages on the client 20 in a form which can be easily interpreted andwhich can be archived for analysis at a later date.

[0033]FIG. 2 shows the preferred system architecture of a client 20 orworkstation 60. The computer system 100 typically comprises a centralprocessor 102, a main memory 104 for example RAM and an input/outputcontroller 106. The computer system 100 may also comprise peripheralssuch as a keyboard 108, a pointing device 110 for example a mouse, trackball or touch pad, a display or screen device 112, a mass storage memory114 for example a hard disk, floppy disk or optical disc, and an outputdevice 116 for example a printer. The system 100 could also include anetwork interface card or controller 118 and/or a modem 120. Theindividual components of the system 100 could communicate through asystem bus 122.

[0034] Alternatively, the workstation 60 or client 20 could comprise anysuitable data carrier or processor for example a handheld data processorand be arranged to communicate with for example the data repository 40over any suitable network 30.

[0035]FIG. 3 illustrates at 200 one example of a display generated bythe system where a merchant operates a retail premises. In this example,a graphical representation of the merchant is generated and displayed.The graphical representation could include a spatial representation ofthe premises of the merchant showing for example shelves 202 and 204 andcounters 206A and 206B. It will be appreciated that the particularrepresentation generated will be varied according to the nature of thedata presented.

[0036] In the example shown in FIG. 3, a display is arranged to displaya contoured representation of customer interest points within the retailpremises. Video cameras 210, 212, 214 and 216 are positioned at astrategic position within the commercial premises. Video camera 214, forexample, is arranged to capture images of customers waiting to be servedat counters 206A and 206B. Images from the cameras 210, 212, 214 and 216are preferably captured and stored in data repository 40, processed bythe workstation 60 and displayed on the client 20 in the form shown inFIG. 3.

[0037] Superimposed on the merchant premises is a contouredrepresentation 220 of a representation of the number of customerspassing through monitored areas captured by video cameras 210, 212, 214and 216. Such customer behaviour could include key performanceindicators for example the number of customers passing through one areaof the representation and could also include the length of time thatindividual customers spend in each area.

[0038] These key performance indicators are displayed as a contouredrepresentation 220 in which areas of large customer traffic, for example230, are indicated in a particular colour and areas of low customertraffic, for example 240, are indicated in a different colour, with arange of colours between the colours of points 230 and 240 showingdifferent ranges of customer traffic. Preferably a legend is provided asindicated at 250 to indicate actual data values represented by thecolours.

[0039] The areas of high customer traffic are preferably represented ina particular colour with areas around these high areas represented togradually drop off or fall away from each point of high interest. Eachdata point could be represented by x and y coordinates indicating therelative position of each data point in the representation. Each datapoint could also have a z value representing the height or magnitude ofthe data point. This z value could indicate, for example, the length oftime spent at a particular data point. Each data value is thereforecentred on a data point.

[0040] The data value of the data point preferably represents the apexof a bell-shaped curve. As x and y values in the representation 200 areincreased or decreased, the z value of the new position in therepresentation will change. Each data point has an axis and a maximumvalue at that axis. At a distance r from the axis, the drop in z valueis preferably calculated by a drop-off function such as the following:${f(r)} = {\frac{1}{1 + \left( \frac{r}{a} \right)}p}$

[0041] The value of p is preferably 2 or 3. As the value of p isincreased, the data point is represented having a steeper shoulder and aflatter peak with steeper walls.

[0042] The value of a defines the horizontal distance between the axisand the point of maximum drop-off of the resulting curve, which inpractice defines the width of the contoured “hill”. The value of a couldbe, for example, the point of “half height” of the hill. Small values ofa will result in fine detail in a contoured representation and largervalues of a will result in a less detailed representation.

[0043] It is envisaged that there are shown a series of data points overthe representation 200 and that values are contoured around these datapoints. Values of a are preferably chosen so that the contouredrepresentation does not display any data values in the areas covered byfor example shelves 202 and 204.

[0044] These KPI values could also be represented in a 3-dimensionalcoordinate system (x_(i), y_(i), z_(i)), where i=1 . . . N. N is thenumber of data points in the finite set which in this case will be thenumber of points through which customer traffic is measured. The (x,y,z)values represent a finite set of data points.

[0045] Each data point is spaced a certain distance from each other datapoint in the finite set. The distance between points i and j, forexample, could be defined as:

(r _(ij))²=(x _(i) −x _(j))²+(y _(i) −y _(j))²

[0046] where r_(ij) is the distance between points i and j.

[0047] In some circumstances, the z values located around a particulardata point will interfere with the z values calculated for neighbouringdata points. The extent to which one data point will interfere withanother data point can be represented as m_(ij), being the height ofhill j at point i. The correct value of each data point is alreadyknown, for example calculated from the data repository 40, and so it isnecessary to calculate a corrective value t to ensure that the z valueat each data point is correct.

[0048] The matrix equation M*T=Z is represented as follows:${\begin{bmatrix}{f\left( r_{11} \right)} & \ldots & {f\left( r_{1N} \right)} \\\ldots & \quad & \ldots \\{f\left( r_{N\quad 1} \right)} & \ldots & {f\left( r_{NN} \right)}\end{bmatrix} \cdot \begin{bmatrix}t_{1} \\\ldots \\t_{N}\end{bmatrix}} = \begin{bmatrix}z_{1} \\\ldots \\z_{N}\end{bmatrix}$

[0049] Matrix M is an N by N matrix having individual valuesM_(ij)=f(r_(ij)). Matrix T is an N by 1 matrix of individual correctivevalues t_(ij). Matrix Z is an N by 1 matrix of individual z valuesz_(i).

[0050] The corrective t_(i) values can be obtained using the knownmethod of solving simultaneous linear equations. Once the correctivet_(i) values are obtained, the remaining points on the surface to berepresented can be calculated from the following equation:${F\left( {x,y} \right)} = {\sum\left\{ {{t_{i}*{f\left( \sqrt{\left( {x - x_{i}} \right)^{2} + \left( {y - y_{i}} \right)^{2}} \right)}},{i = {1\quad \ldots \quad N}}} \right\}}$

[0051] In this way, a curve or surface can be generated which passesthrough two or more known data points for the representation 200,generating values for neighbouring additional data points.

[0052] It is envisaged that the value calculated for an (x,y) positioncorresponding to a shelf, counter or other obstruction be a null value.

[0053] The display could be configured to present to a user on client 20a series of images forming an animated visual image sequence which canbe analysed at a later date. The invention could be arranged, forexample, to present to a user the activity within a retail premises overa 2 hour period by presenting data captured by video cameras and storedin data repository 40 over this 2 hour period to a user. Individualimages preferably include a time and/or date value to enable these datavalues to be displayed in sequential order.

[0054] It is envisaged that the invention could present to a usercontoured representations similar to FIG. 3 of data values from any dataset or plurality of data sets in the data repository 40, for exampledata sets obtained from visual input apparatus 42, audio input apparatus44, traffic counting apparatus 46, pressure sensitive apparatus 48and/or interaction data 50.

[0055] It is also envisaged that where a queue of physical objects forexample people or cars are being monitored at a particular location, theattributes of the objects for example gender or ethnicity and thebehaviour for example irritability, state of agitation or queuemovement, could be recorded with a video camera in order to assess aparticular queue for the required data. The invention is also capable ofmonitoring the movement of groups of people and identifying individualsthat could be loitering in a particular area, either inside or outside apremises, and alert a user to this behaviour, who can then eithermonitor the individuals or approach them directly.

[0056] Contoured representations can be presented of any one or more keyperformance indicators for example the length of the queue, the averagewaiting time in the queue, the average service time, the queue falloff,any service points in a retail establishment, service point throughput,and demographic composition of a queue at any given time.

[0057] The invention could provide a user with a real time tool tooptimise the number of service points, depending on the data displayedon the client 20. For example, if a customer had been waiting in thequeue for more than two minutes, additional service points couldimmediately be opened or staffed.

[0058]FIG. 4 illustrates the preferred method of operation of theinvention. As shown at 300, data is retrieved from the data repository40 using a suitable query. The retrieved data could include data sourcedfrom any one or more of the visual input apparatus 42, audio inputapparatus 44, traffic counting apparatus 46, pressure sensitiveapparatus 48 and interaction data 50.

[0059] As shown at 302, a set of data values is constructed from theretrieved data. This set of data values could include for examplecustomer traffic through a merchant premises.

[0060] It is envisaged that the set of data values could optionally bestored in data memory 62 to increase efficiency of the system, asindicated at 304, which could comprise volatile main RAM or non-volatilemass storage of the workstation 60 on which the invention isimplemented.

[0061] Referring to step 306, the set of data values is retrieved fromthe volatile or non-volatile data memory and as shown at 308, a set ofdata points is constructed to represent the data values. Appropriate xand y values are generated for each data point to space the data pointsover a generated representation.

[0062] Referring to step 310, a contoured representation of the datavalues is generated and displayed on a client 20. The individualdrop-off for each data point is calculated and displayed in theappropriate colour and shading corresponding to the z value at eachpoint.

[0063] It is envisaged that the invention generate individual displaysof contoured representations. It is also envisaged that the inventiongenerate animated sequences of representations by generating two or more“still” representations at various time intervals and superimposingsuccessive representations over earlier representations to generate ananimated sequence.

[0064] As indicated at 312, where such an animated sequence is required,further representations will be needed and if the necessary data isobtainable from the data memory as indicated at 314, it is retrievedfrom the data memory as indicated at 306, otherwise further data isretrieved from the data repository at 300.

[0065] It is envisaged that the invention could be used as a managementtool to visually display the efficiency of each of these service points.In this way, a service point operator spending more than 10 minutes percustomer could be identified as inefficient and appropriate actiontaken.

[0066] By viewing representations produced over a time period, a userwould be able to recognise trends in a queue or crowd. For example, ifmore customers are using a merchant's services after 5.00 pm than duringbusiness hours, then the service provider could increase the number ofservice points operating during these times.

[0067] In a further preferred form, the invention could enable a user tomonitor demographic makeup of a queue or crowd, prompting a serviceprovider to alter advertising, security, services provided or marketingvisual or audio advertising to the customer while in the queue or crowdor receiving a service.

[0068] The invention has the effect that merchants and otherorganisations are provided with an easily interpreted and intuitiverepresentation of data which could be useful in identifying unexpectedtrends in the data.

[0069] The foregoing describes the invention including preferred formsthereof. Alterations and modifications as will be obvious to thoseskilled in the art are intended to be incorporated within the scopehereof, as defined by the accompanying claims.

1. A data visualisation system comprising: a data value memory in whichis maintained a finite set of data values obtained from monitoringapparatus; a display configured to display a representation of each datavalue centred on respective data points; and a contour generatorconfigured to generate and display a contoured representation aroundeach data point such that each data point is displayed as a localmaximum.
 2. A data visualisation system comprising: a data value memoryin which is maintained a finite set of data values obtained frommonitoring apparatus; a display configured to display a representationof each data value centred on respective data points; and a contourgenerator configured to generate and display one or more contour linesaround each data point, each contour line representing data values whichare less than the data value of the data point around which the contourline is displayed.
 3. A data visualisation system as claimed in claim 2further comprising: a memory in which is maintained an interactiondatabase of interaction data representing interactions between customersand merchants; and a retrieval device configured to retrieve from theinteraction database data representing interactions between customersand merchants, to construct the finite set of data values from theretrieved data and to store the data values in the data value memory. 4.A data visualisation system comprising: a data value memory in which ismaintained an interaction database of interaction data representinginteractions between customers and merchants, the interaction dataobtained from monitoring apparatus; a retrieval device configured toretrieve from the interaction database data representing interactionsbetween customers and merchants and to construct a finite set of datavalues from the retrieved data; and a display configured to display agraphical representation of at least one merchant and to superimpose oneor more contoured representations of the data values on the graphicalrepresentation of the merchant such that each data value is displayed asa local maximum.
 5. A data visualisation system as claimed in claim 4wherein at least some of the data values comprise a set of data valuesobtained from processing a series of images captured by monitoringapparatus in the form of visual input apparatus, each set of data valuesincluding a time and/or date value.
 6. A data visualisation system asclaimed in claim 4 wherein at least some of the data values comprise aset of data values obtained from processing a series of segments ofaudio data captured by monitoring apparatus in the form of audio inputapparatus, each set of data values including a time and/or date value.7. A data visualisation system as claimed in claim 4 wherein at leastsome of the data values comprise a set of data values obtained frommonitoring apparatus in the form of traffic-counting apparatus, each setof data values including an integer representing traffic flow and a timeand/or date value.
 8. A data visualisation system as claimed in claim 4wherein at least some of the data values comprise a set of data valuesobtained from monitoring apparatus in the form of pressure-sensitiveapparatus, each set of data values including a time and/or date value.9. A data visualisation system as claimed in claim 4 wherein at leastsome of the data values comprise a set of data values obtained from atelecommunications network, each set of data values representing thenumber of callers in a queue and a time and/or date value.
 10. A methodof data visualisation comprising the steps of: maintaining in a datavalue memory a finite set of data values obtained from monitoringapparatus; displaying a representation of each data value centred onrespective data points; and generating and displaying a contouredrepresentation around each data point such that each data point isdisplayed as a local maximum.
 11. A method of data visualisationcomprising the steps of: maintaining in a data value memory a finite setof data values obtained from monitoring apparatus; displaying arepresentation of each data value centred on respective data points; andgenerating and displaying one or more contour lines around each datapoint, each contour line representing data values which are less thanthe data value of the data point around which the contour line isdisplayed.
 12. A method of data visualisation as claimed in claim 11further comprising the steps of: maintaining in a memory an interactiondatabase of interaction data representing interactions between customersand merchants; retrieving from the interaction database datarepresenting interactions between customers and merchants; constructingthe finite set of data values from the retrieved data; and storing thedata values in the data value memory.
 13. A method of data visualisationcomprising the steps of: maintaining in a memory an interaction databaseof interaction data representing interactions between customers andmerchants, the interaction data obtained from monitoring apparatus;retrieving from the interaction database data representing interactionsbetween customers and merchants; constructing a finite set of datavalues from the retrieved data; displaying a graphical representation ofat least one merchant; and superimposing a contoured representation ofthe data values on the graphical representation of the merchant suchthat each data value is displayed as a local maximum.
 14. A method ofdata visualisation as claimed in claim 13 further comprising the step ofobtaining at least some of the data values from processing a series ofimages captured by monitoring apparatus in the form of visual inputapparatus, each set of data values including a time and/or date value.15. A method of data visualisation as claimed in claim 13 furthercomprising the step of obtaining at least some of the data values fromprocessing a series of segments of audio data captured by monitoringapparatus in the form of audio input apparatus, each set of data valuesincluding a time and/or date value.
 16. A method of data visualisationas claimed in claim 13 further comprising the step of obtaining at leastsome of the data values from monitoring apparatus in the form oftraffic-counting apparatus, each set of data values including an integerrepresenting traffic flow and a time and/or date value.
 17. A method ofdata visualisation as claimed in claim 13 further comprising the step ofobtaining at least some of the data values from monitoring apparatus inthe form of pressure-sensitive apparatus, each set of data valuesincluding a time and/or date value.
 18. A method of data visualisationas claimed in claim 13 further comprising the step of obtaining at leastsome of the data values from a telecommunications network, each set ofdata values representing the number of callers in a queue and a timeand/or date value.
 19. A data visualisation system comprising: a finiteset of discrete data values maintained in computer memory, the datavalues obtained from monitoring apparatus; a display configured todisplay a representation of each data value centred on respective datapoints; and a contour generator configured to generate and display acontoured representation around each data point such that each datapoint is displayed as a local maximum.
 20. A data visualisation systemcomprising: a finite set of discrete data values maintained in computermemory, the data values obtained from monitoring apparatus; a displayconfigured to display a representation of each data value centred onrespective data points; and a contour generator configured to generateand display one or more contour lines around each data point, eachcontour line representing data values which are less than the data valueof the data point around which the contour line is displayed.
 21. A datavisualisation system as claimed in claim 20 further comprising: aninteraction database maintained in computer memory of interaction datarepresenting interactions between customers and merchants; and aretrieval device configured to retrieve from the interaction databasedata representing interactions between customers and merchants, toconstruct the finite set of discrete data values from the retrieved dataand to store the data values in computer memory.
 22. A datavisualisation system comprising: an interaction database maintained incomputer memory of interaction data representing interactions betweencustomers and merchants, the interaction data obtained from monitoringapparatus; a retrieval device configured to retrieve from theinteraction database data representing interactions between customersand merchants and to construct a finite set of discrete data values fromthe retrieved data; and a display configured to display a graphicalrepresentation of at least one merchant and to superimpose one or morecontoured representations of the data values on the graphicalrepresentation of the merchant such that each data value is displayed asa local maximum.
 23. A data visualisation system as claimed in claim 22wherein at least some of the data values comprise a set of data valuesobtained from processing a series of images captured by monitoringapparatus in the form of visual input apparatus, each set of data valuesincluding a time and/or date value.
 24. A data visualisation system asclaimed in claim 22 wherein at least some of the data values comprise aset of data values obtained from processing a series of segments ofaudio data captured by monitoring apparatus in the form of audio inputapparatus, each set of data values including a time and/or date value.25. A data visualisation system as claimed in claim 22 wherein at leastsome of the data values comprise a set of data values obtained frommonitoring apparatus in the form of traffic-counting apparatus, each setof data values including an integer representing traffic flow and a timeand/or date value.
 26. A data visualisation system as claimed in claim22 wherein at least some of the data values comprise a set of datavalues obtained from monitoring apparatus in the form ofpressure-sensitive apparatus, each set of data values including a timeand/or date value.
 27. A data visualisation system as claimed in claim22 wherein at least some of the data values comprise a set of datavalues obtained from a telecommunications network, each set of datavalues representing the number of callers in a queue and a time and/ordate value.
 28. A method of data visualisation comprising the steps of:maintaining in computer memory a finite set of discrete data valuesobtained from monitoring apparatus; displaying a representation of eachdata value centred on respective data points; and generating anddisplaying a contoured representation around each data point such thateach data point is displayed as a local maximum.
 29. A method of datavisualisation comprising the steps of: maintaining in computer memory afinite set of discrete data values obtained from monitoring apparatus;displaying a representation of each data value centred on respectivedata points; and generating and displaying one or more contour linesaround each data point, each contour line representing data values whichare less than the data value of the data point around which the contourline is displayed.
 30. A method of data visualisation as claimed inclaim 29 further comprising the steps of: maintaining in computer memoryan interaction database of interaction data representing interactionsbetween customers and merchants; retrieving from the interactiondatabase data representing interactions between customers and merchants;constructing the finite set of discrete data values from the retrieveddata; and storing the data values in computer memory.
 31. A method ofdata visualisation comprising the steps of: maintaining in computermemory an interaction database of interaction data representinginteractions between customers and merchants, the interaction dataobtained from monitoring apparatus; retrieving from the interactiondatabase data representing interactions between customers and merchants;constructing a finite set of discrete data values from the retrieveddata; displaying a graphical representation of at least one merchant;and superimposing a contoured representation of the data values on thegraphical representation of the merchant such that each data value isdisplayed as a local maximum.
 32. A method of data visualisation asclaimed in claim 31 further comprising the step of obtaining at leastsome of the data values from processing a series of images captured bymonitoring apparatus in the form of visual input apparatus, each set ofdata values including a time and/or date value.
 33. A method of datavisualisation as claimed in claim 31 further comprising the step ofobtaining at least some of the data values from processing a series ofsegments of audio data captured by monitoring apparatus in the form ofaudio input apparatus, each set of data values including a time and/ordate value.
 34. A method of data visualisation as claimed in claim 31further comprising the step of obtaining at least some of the datavalues from monitoring apparatus in the form of traffic-countingapparatus, each set of data values including an integer representingtraffic flow and a time and/or date value.
 35. A method of datavisualisation as claimed in claim 31 further comprising the step ofobtaining at least some of the data values from monitoring apparatus inthe form of pressure-sensitive apparatus, each set of data valuesincluding a time and/or date value.
 36. A method of data visualisationas claimed in claim 31 further comprising the step of obtaining at leastsome of the data values from a telecommunications network, each set ofdata values representing the number of callers in a queue and a timeand/or date value.